Chunk #22 — Results — The relative molecular mass (Mr) of MOPR in G/G mice was lower than that in A/A mice, which is due to differences in N-glycosylation of MOPR
We then tested the hypothesis that the differences in the Mr's of the MOPRs in A/A and G/G are due to varying extents of glycosylation from the loss of one glyclosylation site (N38) in the G/G mice. To this end, we enriched MOPRs by wheat germ lectin (WGL) affinity chromatography [29] and treated the MOPRs with PNGase F, which removes all N-linked glycans. Thalamic membranes of A/A or G/G mice (half males and half females) were pooled and solubilized with 2% Triton X-100 and incubated with WGL Sepharose 6MB beads and eluted with 5% SDS, which enriched the MOPR approximately 30-fold. Western blotting of WGL affinity-purified materials with anti-mu C showed that the thalamic MOPRs in A/A and G/G mice migrated as a single diffuse band with a median Mr of 62 kDa and 55 kDa (Fig. 3, lanes 1 and 2), respectively. Treatment of the WGL affinity-purified materials with PNGase F resulted in an increase in the mobility of thalamic MOPRs in both A/A and G/G mice on SDS–PAGE (Fig. 3, lanes 3 and 4), compared with the untreated
